I swapped out my rotors the other day and when I went to take off the caliper assembly on the right rear side, two out of three of the clips "holding" the pad onto the piston broke off (heat over time and my wiggling weren't friendly I guess). I put it back together just fine minus those two clips, but I am wondering whether I am risking something going wrong. I can't think of anything bad happening offhand, but that's why I'm sticking it up on the boards. For reference, I am running the Hawk HPS's.

So, thoughts?

- Matt

 

Wow...nothing?

Bump.

- Matt

 

FWIW - I was always told that those clips on rear pads were to prevent noise. Never researched it any further though.

And one pad on my 03 MINI was missing all of the clips when I changed my pads a few months ago. I don't know how long the clips had been missing, but they never made a squeak before they were replaced after the sensor wore down.

 

Wow...exactly the response I hoped I would get. Do you know if you were getting uneven pad or rotor wear?

Thanks for the response.

- Matt

 

My understanding is that those clips are necessary in order to keep the pads from dragging on the rotor, greatly increasing the wear on both.

 

Good to get a thought on the other side. Can you explain further?

- Matt

 

check out posts # 36 forward, in particular # 57:

https://www.northamericanmotoring.co...ad.php?t=43438

 

Prior to this post, I called up a buddy of mine and we discussed it. We covered the fact that the clips for the front pads are primarily and near solely for noise, the rear pads possibly being likewise. We initially (and currently) think this makes the most sense, as the tensile strength and so forth of the clips isn't nearly enough to keep it firmly in place on load...it's acting more as a damping mechanism.

Next we discussed the merits of the clips pulling the pad back when not braking. He was of the mind that the pads are damn near always in contact with the rotor anyways, barely gliding over them on a surface of air and light particulates/dust/pad material. There would not be enough pressure on the pad without pressing the brake pedal for it to cause substantial drag on the rotor. If you think about it, the caliper never really "retracts" per se...it extends when the pedal is depressed, and is pushed slightly back by frictional forces on the rotor.

I've taken the car for a drive to make sure everything was hunky-dory anyways, and I'm not getting any pull to the right side while coasting, nor any clicking on the slotted rotors...

Octaneguy brings some empirical evidence to the table with that post in the thread you referenced, but I have to wonder if that really was the problem....there's not much in the way of details there.

Keep in mind, I definitely appreciate the links there. I am indeed trying to get opinions on both sides of this. I am also trying to keep in mind my own bias as to wanting to believe this won't cause a problem. I am a perfectionist though (so that helps me be at least a bit objective ). Logically/functionally I can't theorize there being any problem, but at the same time you've pointed to possible empirical evidence, albeit only one data point somewhat lacking in explanation. Neither can be denied though.

I just hope I don't have to spend another $90 for a rear set due to one ******** clip. I barely have any miles on these pads!

- Matt

 

I'd agree with that...my car is still on stock rear pads and my interior is gutted, letting me hear a lot more that is going on back there. Nothing scientific or mechanical to add...just what I gleaned from listening.

 

is that the piston DOES retract. This is the function of the square o-ring. It sheers when the piston extends, and provides a restoring force to withdraw the piston a bit (doesn't need much). Now, what's interesting is that the clips only hold the pad against the piston, but it's a sliding caliper design, so the other side is left to rattle and clank as needed, and there is no shear force to pull it away from the rotor.

I have no clue why they are there, as far as I can tell, they really don't serve any purpose other than to drive up the cost of the pads.

Ask ToddTCE, he's really knowledgible about brakes....

Matt

 

Yeah...I mean, it retracts, but in my mind the function of the clips is not to aid in said retraction...the retraction itself is of such a small degree to as be negligible in this equation (I think).

But yeah, that was also my thinking with the outer pads -> no clips whatsoever.

Odd...I may have to get in touch with him, or some other industry expert on brake pads.

- Matt

 

I'd guess it keeps rattles down, and that's about it. It won't dampen anything, as the material isn't what's known as lossy.

Floating calipers decrease friction when not braking by having the piston retract, and the contact with the outer pad then pushes the caliper a bit. Since no rotor is completely flat, this helps move the caliper, and when not braking, there is little force on the slides so the friction holding them in place is small too. But anyway, this is all just more reasons that floating caliper designs are less than ideal.

Matt

 

This is what I've been thinking and would make sense, considering how the fronts operate.

Almost put me on the search for a new caliper setup. Alas, I am poor.

Thanks for the added input.

I'll follow up if I get any issues.

- Matt